• Title/Summary/Keyword: force support system

Search Result 334, Processing Time 0.032 seconds

Dynamic Response Optimization of a Mobile Harbor Crane with a Moving Support (지지부가 움직이는 모바일하버용 크레인의 동적 응답 최적설계)

  • Kim, Hyun-Bum;Lee, Jae-Jun;Jang, Hwan-Hak;Park, Gyung-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.36 no.5
    • /
    • pp.497-504
    • /
    • 2012
  • The mobile harbor is a new innovative system that delivers containers from a containership to a harbor without good infrastructure. A crane is installed on the deck of the mobile harbor and transfers the containers. The structure of the crane is influenced by the inertia force that occurs from a moving support. Thus an accurate safety verification considering the moving support is required. Lightweight of the crane structure is also significant in the design for low production cost and efficient operation. Dynamic response optimization can be exploited to achieve these two requirements. Equivalent static loads method is employed for dynamic response optimization of the crane. The equivalent static loads method transforms dynamic loads to equivalent static loads, and static response structural optimization with the transformed equivalent static loads are solved. The process proceeds in a cyclic manner. A new method is proposed to consider the moving supports and the structure of the mobile harbor is optimized using the proposed method.

Motion Analysis and EMG Analysis of the Pelvis and Lower Extremity according to the Width Variation of the Base of Support

  • Yoo, Kyung-Tae;Yoon, Jung-Gyu;Park, Bo-Kyung;Han, Hae-Rin;Yun, Young-Dae;Lee, Sang-Bin
    • Journal of International Academy of Physical Therapy Research
    • /
    • v.3 no.1
    • /
    • pp.391-396
    • /
    • 2012
  • The purpose of this study is to identify which width of the base of support(BOS) is safer and more effective in lifting by comparing muscle activations and body sways when lifting objects under the width variation of the BOS. A total of fifteen healthy adults participated in this study. For the width variation of the BOS, the participants changed the width between their feet into three different types(10cm, 32cm, 45cm) and lifted a 10kg four times in each type after going up on a force plate. In order to measure body sways according to the width variation of the BOS, a motion analysis system was used. In addition, in order to measure the muscle activations of lower extremities, including the erector spinae, gluteus maximus, rectus femoris, and tibialis anterior, an electromyogram(EMG) analysis was employed. In addition, the Borg's scale was drawn by quantifying the subjective discomfort levels felt from each width of the BOS. In conclusion, no statistically significant differences according to the width variation of the BOS were observed(p=.295, .308)(p>.05). However, a statistically significant difference was exhibited between the Borg's scale, which indicates the discomfort levels from lifting performances, and the width variation of the BOS (p=$.000^*$).

Geometric nonlinear analysis of steel structures with external pretension using the multi-noded cable element (다절점 케이블요소를 이용한 외부 긴장된 강구조 시스템의 기하학적 비선형해석)

  • Lee, Jun Seok;Kim, Moon Young;Han, Man Yop;Kim, Sung Bo;Kim, Nak Kyung
    • Journal of Korean Society of Steel Construction
    • /
    • v.18 no.6
    • /
    • pp.727-735
    • /
    • 2006
  • In this paper, a geometric nonlinear analysis procedure of the beam-column element including multi-noded cable element in extension of companion paper (Kim et al., 2005) is presented. First, a stiffness matrix was derived about the beam-column element that considers the second effect of the initial force supposing the curved shape at each time-step, with Hermitian polynomials as the shape function. Second, the multi-noded cable element was also subjected to the tangent stiffness matrix. To verify the geometric nonlinearity of this newly developed multi-noded cable-truss element, the Innovative Prestressed Support (IPS) system using this theory was analysed by geometric nonlinear method and the results were compared with those produced by linear analysis.

A Study on the IUU Governance System of Regional Fishery Management Organization and Major State (국제 지역 수산 관리 기구와 주요 국가의 IUU 통제제도 연구)

  • Park, Min-Gyu
    • The Journal of Fisheries Business Administration
    • /
    • v.41 no.3
    • /
    • pp.103-127
    • /
    • 2010
  • The FAO reports that IUU fishing activities have widespread economic, social, and management consequences, including depriving legitimate fishers of harvest opportunities. It affects all fisheries from small scale to industrial. It also affects the ability of governments to support sustainable livelihoods for fishers and, more broadly, to achieve food security. The complexity of IUU requires various measures to combat IUU fishing such as adoption of IUU vessel lists; stronger port State controls; improved monitoring, control and surveillance (MCS); implementation of market-related measures to help ensure compliance; and capacity-building assistance. Trade and market measures reduce opportunities for IUU fishing activities by precluding or impeding access to markets for IUU product in a manner consistent with international law. ICCAT, CCAMLR, and IATTC, have put in place trade tracking programs or catch documentation schemes, and WCPFC is considering such a program. Vessel lists assist enforcement authorities in determining which vessels are or are not authorized to be fishing or conducting fishing support activities in specified areas. A number of RFMOs maintain records of IUU vessels: CCAMLR, IATTC, ICCAT, NAFO, NASCO, NPAFC, WCPFC. Section 608 of the US MSRA calling on the Secretary of Commerce, in consultation with the Secretary of State, and in cooperation with relevant regional fishery management councils and any relevant advisory committees, to take actions to improve the effectiveness of international fishery management organizations in conserving and managing stocks under their jurisdiction. EU IUU Regulation entered into force on 1 January 2010, was intended to regulate the highly complex multi-channel fisheries supply system of the European Community (EC) in an effort to improve global fisheries sustainability.

Investigation of the Potential Risk for Musculoskeletal Disorders in Migrant Workers (외국인근로자의 근골격계질환 발생가능성에 관한 연구)

  • Lim, Hyung-Duk;Rajitha Kawshalya, Mailan Arachchige Don;Nam, Ki-Hun
    • Journal of the Korean Society of Industry Convergence
    • /
    • v.24 no.6_2
    • /
    • pp.781-786
    • /
    • 2021
  • Korean domestic workers are trend to avoid harmful and dangerous jobs calls 3D work due to the poor working conditions. Therefore, the incoming population of foreign workers is increasing to fulfill the required labor force. Mostly these foreign workers are placed in small and medium-size industries. As work that induces musculoskeletal disorders(WMSD) is equally exposed to domestic workers as well as foreign workers, this study attempted to investigate the work burdened by musculoskeletal disorders and derive improvement measures by understanding the actual conditions of the worksites of foreign workers. The result of this investigation defines that the possibility of developing musculoskeletal disorders is very high in the environment in which more than 40% of the respondents work with heavy objects and repetitive work of wrists and elbows. To prevent the symptoms of musculoskeletal disorders among foreign workers, three measures were proposed. To reduce the mandatory check-up period of WMSD under the Occupational Safety and Health Act, to revise the employment permit system, and to enhance the practical help of EPS education. Safety and health management of foreign workers is becoming an essential task not only for securing a workforce but also for the national image. Personal and economic losses at the national level should be minimized through policy support such as financial support for small and medium-sized businesses in Korea and supplementation of legal systems for the protection of foreign workers.

New Sizing System Development of Korean Male Military Winter Jacket (한국 남자 군인 방한복의 신 치수체계 개발)

  • Han, Hyunsook;Han, Hyunjung;Cho, Jayoung;Jung, Kihyo;Kim, Beomjoon;Koh, Joonseok;Park, Changkyu
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.40 no.5
    • /
    • pp.954-965
    • /
    • 2016
  • This study was designed to help develop an optimized sizing system for the military winter jackets of Korean males. First, we conducted a survey on the supply rate of military winter jackets and the wearing of suitable size jackets in order to identify problems in the current sizing system. We next developed a new sizing system generation method to satisfy the coverage rate and appropriate size number: Hybrid of Grid with Optimization. The findings of this study were: 1. The survey indicated that a 90 (chest girth) size is necessary; in addition, a one-step large size jacket fit well as a right size jacket. 2. We developed three optimized sizing systems for Korean male military winter jackets using the Hybrid of Grid with an optimization method and suggested one of them as a final new sizing system. The new sizing system consisted of two primary dimension: chest girth and stature. It has a 14 size number and its extended coverage rate is larger than the current sizing system and it has a 90 (chest girth) size. It also selected an optimized size for the area of low population density. The new sizing system is therefore considered very effective for Korean male soldiers military winter jackets.

Configuration and Design of the Large Multi-Electromagnetic Shaking System (대형 멀티 전자기 가진 시스템의 구성 및 설계)

  • 우성현;김홍배;문상무;김영기;임종민
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2004.05a
    • /
    • pp.618-622
    • /
    • 2004
  • The vibration test system of SITC(Satellite Integration and Test Center) at KARI(Korea Aerospace Research Institute) has been used successfully for the environmental tests of a majority of korean space programs, such as KOMPSAT, Koreasat KITSAT, STSAT and KSR program since 1996. To meet the recent needs of large size test facility available for the vibrational tests of the huge launch vehicles and tole-communication satellites which will be developed in the near future, KARI undertook to construct the large size multi-electromagnetic shaking system with 3 $\times$ 3m head expander system. The new system will consist of three electromagnetic shakers which has 160 kN thrust force individually, and be able te sustain up to 8 tons test load and 300 kNm overturing moment. And to avoid the tremendous cost and effort to furnish the seismic block with large size and weight, it will adopt a Lin-E-Air type configuration with which the seismic block is less severe than a Solid-Truninon type. In addition, to fulfill the strong requirement of high overturning moment the additional guidance system including a central bearing system on a central support and several pad bearings around the head expander body is now considered. This paper describes the configuration and the design parameters of the multi-shaking system which is under development by KARI's engineers.

  • PDF

Analysis and Design of Soft Ground Tunnels Subject to Steady-State Groundwater Flow (정상류 조건하의 토사터널의 해석 및 설계)

  • Lee, In-Mo;Nam, Seok-Woo;Lee, Myung-Jae
    • Geotechnical Engineering
    • /
    • v.10 no.2
    • /
    • pp.41-56
    • /
    • 1994
  • Under the groundwater level, the tunnel face is affected by the seepage force and the groundwater flow may cause a trouble to the tunnel support systems. The appropriate methods of analysis and design in the tunnel face and the lining, considering groundwater flow according to tunnel drainage condition are presented in this thesis. First, the effect of seepage on the stability of tunnel face was studied. Seepage force was estimated by the 3-D finite element analysis and the stability of tunnel face was checked by analytical method. Furthermore, using the finite difference method the stress and displacement on the face were computed for either case, where the seepage force is or is not considered, and the effect of seepage on the tunnel face stability was evaluated. Second, the effect of seepage force on the tunnel lining when construction is finished and steady state seepage flow occurs was studied and a design methodology considering seepage effect was made. Consequently, in case where the groundwater level remains almost unchanged and the steady state groundwater flow occurs, the proper countermeasures for face staility are required according to the condition of groundwater flow. Moreover, the tunnel lining should be designed and constructed considering the seepage force occuring by the groundwater flow toward the tunnel linings.

  • PDF

Concept Design Method of Smart City using Defense System Development Process of DoD (미국방성의 전력개발 프로세스를 활용한 스마트 시티 개념설계 방안)

  • Lee, Joong Yoon
    • Journal of the Korean Society of Systems Engineering
    • /
    • v.15 no.2
    • /
    • pp.98-107
    • /
    • 2019
  • The defense system development process is a process of developing various systems that perform functions in various functional areas such as battlefield awareness, command control, force application, and logistical support. In other words, the defense system development process is a process of developing many systems simultaneously in various functional areas. Various systems developed through this process should be interoperable so that they can be integrated and operated in a joint warfighting environment. To successfully implement this, the US Department of Defense uses the Joint Capability Integrated Development System(JCIDS) for the defense system development, and within this JCIDS processes the Capability Based Assessment(CBA) methodology as its core technology. This CBA methodology transforms the mission activity requirements to functional capability requirements logically and transforms the functional capability requirements to system requirements logically also. Smart City is a city that improves the convenience and quality of life of the citizen by integrates various systems that perform various functions of the city and smarties various functional systems with smart services by using IT technology. In other words, defense system development and smart city development have a common feature of the process of developing many systems simultaneously in various functional areas. In order to address the problem of having to develop many systems simultaneously in each functional area, it is important to logically transform the various mission scenarios into functions and logically transform the functions into systems. Therefore, a joint capability integrated development system and its core methodology, Capability Based Assessment(CBA), can be applied to smart city development. This paper proposes a method for performing a smart city concept design method using the capability based evaluation (CBA) method.

Effective Methods Reducing Joint Vibration and Elongation in High speed Rail Bridge (고속철도교 신축부의 진동 및 신축의 효율적인 저감 방안)

  • Min, Kyung-Ju;Kang, Tae-Ku;Lim, Nam-Hyoung
    • Proceedings of the KSR Conference
    • /
    • 2011.10a
    • /
    • pp.800-806
    • /
    • 2011
  • Thermal expansion which occurs at the high speed rail joint is proportional to the free length from the point of fixity. This thermal expansion behaves similar to free expansion because the girder longitudinal stiffness is much larger than longitudinal resistance of rail pads. But the longitudinal displacement in the long rail is nominal because the longitudinal support condition of the girder is normally MFM(movable-fix-movable) system. Due to these girder expansion characteristics, there is longitudinal relative displacement at the rail pad and rail fastener spring which connects rail and girder. If the relative displacement between rail and girder is beyond the elastic limit for the rail pad, rail fastener system shall be applied using sliding fastener to prevent rail pad damage and fastener separation resulting from slip. On the other hand, train vertical vibration and tilting can occur due to the lack of fastener vertical force if the sliding fastener is applied at the girder joint. In the high speed rail bridge, vibration can occur due to the spring stiffness of the elastomeric bearing, also both vertical downward and upward displacement can occur. The elastomeric bearing vertical movement can cause rail displacement and finally the stability of the ballast is reduced because the gravel movement is induced.

  • PDF